Manually operated impact tool

ABSTRACT

A manually operated rotatable impact tool including: a driven member having means for retaining and driving a fastener about an axis, the driven member further having at least one impact stop offset from the axis; a driving member rotatably connected to the driven member for driving the driven member about the axis to loosen or tighten the fastener; an impact mass movable along a path in communication with the impact stop; a spring disposed in the path for storing energy upon rotation of the driving member; and an energy releasing mechanism for releasing the stored energy and allowing it to be at least partially transferred to the impact mass such that the impact mass accelerates and strikes the impact stop upon the release of the stored energy.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/121,480 filed Apr. 11, 2003, which is a conversion of and claims thebenefit of provisional applications 60/283,581 filed on Apr. 13, 2001and 60/355,870 filed on Feb. 11, 2002, all of which are entitled“Manually Operated Impact Tool.” The disclosures of 10/121,480;60/283,581; and 60/355,870 are incorporated herein in their entirety bytheir reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to impact tools and, moreparticularly, to manually operated impact tools such as an impact wrenchwhich tightens or loosens a nut from a mating threaded shaft.

2. Prior Art

Impact based or impact assisted wrenches of the prior art operate usingelectric, pneumatic and in some cases hydraulic power to loosen and/ortighten fasteners such as nuts threaded on a mating treaded stud. Theimpact force generated by such wrenches greatly assists the looseningand tightening operation of such devices by generating a large impulsiveforce at the fastener interface. As the result, and in many cases duealso to the generated stress waves that travels across the male andfemale fastener surfaces, such wrenches are operated with asignificantly smaller operator effort. In certain situations, the largeforces and/or moment and/or torque that has to be applied to a manuallyoperated wrench to begin to open the fastener may cause its failure,particularly since such forces cannot usually be applied perfectlysymmetrically, i.e., only in the direction that would open the fastenerwithout unwanted added forces. For example, an operator applying atorque to a manually operated socket wrench to open a bolt may alsoapply a large shearing force and/or bending moment while exerting hismaximum effort to open the fastener and thereby may cause the bolt toshear off during the procedure. Such failures seldom occur while usingimpact based wrenches since the operator does not have to exert his orher maximum effort in the above manner to operate the wrench.

It can safely be claimed that the relative ease with which impact basedwrenches are operated to loosen or tighten various fasteners is wellappreciated by their users. However, such wrenches require electric,pneumatic or some other type of generally electric based power in orderto operate. In addition, such systems are generally heavy, bulky andexpensive to be carried by the operator to all sites. This isparticularly the case for the infrequent user such as a driver who mayrequire the wrench in case of a flat tire to loosen and fasten the tirebolts or nuts.

A need therefore exists in the art for manually operated impact wrenchesthat are simple to use, light weight and inexpensive, particularly forthe casual user and professional user who does not have access to apower source at the work site or who does not want to carry a heavy loadto a site or may seldom face the need for its use.

SUMMARY OF THE INVENTION

Therefore it is an object of the present invention to provide a manuallyoperated impact tool which offers the same advantages as thepneumatically and electrically powered impact tools of the prior art.

Accordingly, a manually operated rotatable impact tool is provided. Theimpact tool comprises: a driven member having means for retaining anddriving a fastener about an axis, the driven member further having atleast one impact stop offset from the axis; a driving member rotatablyconnected to the driven member for driving the driven member about theaxis to loosen or tighten the fastener; an impact mass movable along apath in communication with the impact stop; a spring disposed in thepath for storing energy upon rotation of the driving member; and energyreleasing means for releasing the stored energy and allowing it to be atleast partially transferred to the impact mass such that the impact massaccelerates and strikes the impact stop upon the release of the storedenergy.

The fastener can be a hexagonal nut and the means for retaining anddriving the hexagonal nut comprises a mating hexagonal recess forcontaining the hexagonal nut therein.

The driven member can be cylindrical where the driving member has amating cylindrical recess for containing the driven member therein. Thedriving member can further have a lever for applying a torque to thedriven member and hexagonal nut contained therein.

The impact tool can further comprise an abutment on the driving member,wherein the spring is a compression spring disposed in the path betweenthe abutment and the impact mass.

The impact tool can further comprise adjustment means for varying apredetermined angular rotation of the impact mass and thereby the amountof energy stored in the impact mass at the time of releasing the impactmass to strike the impact stop.

Rotation of the driving member in a first angular direction can loosenthe fastener. Rotation of the driving member in a first angulardirection can tighten the fastener. Rotation of the driving member in afirst angular direction can loosens the fastener and rotation of thedriving member in a second angular direction opposite the first angulardirection can tighten the fastener.

The impact mass can strike the impact stop upon the rotation of thedriving member in a first angular direction and the impact mass canstrike the impact stop subsequently by rotation of the driving member ina direction opposite the first angular direction followed by rotation ofthe driving member in the first angular direction. The impact mass canstrike the impact stop upon the rotation of the driving member in afirst angular direction and the impact mass can strike the impact stopsubsequently by continued rotation of the driving member in the firstangular direction.

Also provided is a manually operated rotatable impact tool comprising: adriven member having means for retaining and driving a fastener about anaxis, the driven member further having at least one anvil surface offsetfrom the axis; a driving member rotatably connected to the driven memberfor driving the driven member about the axis to loosen or tighten thefastener, the driving member having at least one anvil in cooperationwith the at least one anvil surface; biasing means for biasing the atleast one anvil surface and at least one anvil together; at least onecam for engaging a surface of the driving member and for moving the atleast one anvil apart from the corresponding at least one anvil surfaceupon rotation of the cam and for releasing the driving member such thatthe spring pulls the at least one anvil to impact the corresponding atleast one anvil surface to create a torque around the axis.

The cam can have two or more cam surfaces each of which engages thesurface of the driving member.

The at least one cam can be rotatably disposed in the driven member. Inwhich case, the at least one cam can comprise two cams, each rotatablydisposed in the driven member and equally distanced from the axis.

Still provided is a manually operated rotatable impact tool comprising:a driven member having means for retaining and driving a fastener aboutan axis, the driven member further having at least one anvil offset fromthe axis, the anvil being rotatably disposed in the driven member intoand out from a path; a driving member rotatably connected to the drivenmember for driving the driven member about the axis to loosen or tightenthe fastener; an impact mass movable along the path in communicationwith the at least one anvil; a flexible member connecting the drivingmember and impact mass for storing energy upon rotation of the drivingmember; and energy releasing means for releasing the stored energy andallowing it to be at least partially transferred to the impact mass suchthat the impact mass accelerates and strikes the at least one anvil uponthe release of the stored energy while the at least one anvil is rotatedinto the path.

The at least one anvil can comprise first and second anvils, each of thefirst and second anvils being rotatably disposed in the driven memberinto an out from the path, the impact mass being held against the firstanvil upon rotation of the driving member due to a biasing force exertedby the flexible member, wherein the energy releasing means comprises afollower plate rotatably disposed in the driven member, the followerplate having at least one arm for engaging the first anvil and rotatingthe first anvil out from the path causing the impact mass to rotate andimpact the second anvil. The follower plate can further have at leastone leg which when rotated does not interfere with the first and secondanvils and further comprising a spring connecting the leg to the impactmass for biasing the impact mass toward one of the first or secondanvils.

The driven member can comprises a shell having a wall, the at least oneanvil being rotatably disposed in the wall.

The impact wrench can further comprise a biasing means for biasing theat least one anvil into the path.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the apparatus ofthe present invention will become better understood with regard to thefollowing description, appended claims, and accompanying drawings where:

FIG. 1 illustrates a partial side sectional view of a generalrepresentation of the impact tool of the present invention.

FIG. 2A illustrates a sectional view of a first configuration of animpact wrench of FIG. 1 taken along line 2-2 of FIG. 1 in which theimpact wrench is of a loosening configuration and where the impact massstrikes the impact stop upon the rotation of the driving member in afirst angular direction and the impact mass strikes the impact stopsubsequently by rotation of the driving member in a direction oppositethe first angular direction followed by rotation of the driving memberin the first angular direction.

FIG. 2B illustrates a sectional view of a second configuration of animpact wrench of FIG. 1 taken along line 2-2 of FIG. 1 in which theimpact wrench is of a tightening configuration and where the impact massstrikes the impact stop upon the rotation of the driving member in afirst angular direction and the impact mass strikes the impact stopsubsequently by rotation of the driving member in a direction oppositethe first angular direction followed by rotation of the driving memberin the first angular direction.

FIG. 2C illustrates a sectional view of a third configuration of animpact wrench of FIG. 1 taken along line 2-2 of FIG. 1 in which theimpact wrench is of a loosening configuration and where the impact massstrikes the impact stop upon the rotation of the driving member in afirst angular direction and the impact mass strikes the impact stopsubsequently by continued rotation of the driving member in the firstangular direction.

FIG. 2D illustrates a sectional view of a fourth configuration of animpact wrench of FIG. 1 taken along line 2-2 of FIG. 1 in which theimpact wrench is of a tightening configuration and where the impact massstrikes the impact stop upon the rotation of the driving member in afirst angular direction and the impact mass strikes the impact stopsubsequently by continued rotation of the driving member in the firstangular direction.

FIGS. 3A-3F illustrate the positions of the driving member, impact mass,impact stop, stop mover, and movable stop plates at different timesthroughout the angular movement of the driving member as if the angularmovement were linear.

FIG. 4A illustrates a front view of either of the movable stop plates asviewed about lines 4A-4A of FIG. 3A.

FIG. 4B illustrates a side view of either of the movable stop plates asviewed about lines 4B-4B of FIG. 3A.

FIG. 5 illustrates a sectional view of the impact stop as taken alongline 5-5 of FIG. 3E.

FIG. 6 illustrates an impact tool in the form of a wrench havingtightening and loosening portions, switching means for switching betweenthe loosening and tightening portions, and locking means for locking theeither of the loosening and tightening portions to communicate with afastener.

FIG. 7 illustrates an impact tool in the form of a wrench havingtightening and loosening portions, wherein the loosening and tighteningportions are provided at opposite ends of the impact tool.

FIG. 8 illustrates a plan view of a first embodiment of a manuallyoperated rotatable impact wrench of the present invention.

FIG. 9 illustrates a side view of the manually operated rotatable impactwrench of FIG. 8.

FIG. 10 illustrates a plan view of a second embodiment of a manuallyoperated rotatable impact wrench of the present invention.

FIG. 11 illustrates a side view of the manually operated rotatableimpact wrench of FIG. 10.

FIG. 12 illustrates an alternative lifter cam for use in either of thefirst and second embodiments of FIGS. 8 and 10, respectively.

FIG. 13 illustrates a variation of the second embodiment of the impactwrench of FIG. 10 in which two near simultaneous impacts are produced.

FIGS. 14A-14D illustrate a third embodiment of the impact wrench of thepresent invention.

FIG. 15 illustrates a schematic illustration of a manually operatedimpact cutting tool.

FIG. 16 illustrates a schematic illustration of a manually operatedimpact punching tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Although the present invention is applicable to numerous types of impacttools, it is particularly useful in the environment of impact wrenches.Therefore, without limiting the applicability of the present inventionto impact wrenches, it will be described in such environment.

Referring now to FIG. 1, there is illustrated a general representationof the impact tool 100 of the present invention configured to be adaptedto a hexagonal nut 102 for tightening and/or loosening the nut 102 froma mating threaded stud 104. The hexagonal nut 102 is illustrated by wayof example only and not to limit scope of the present invention. Itshould be appreciated by those skilled in the art that the impact tool100 of the present invention can be adapted to any fastener that can betightened and/or loosened, such as various types of screws, nuts, andbolts, and can even be adapted to open screw-on jar lids and the like.As will be apparent to those skilled in the art, the impact tools 100 ofthe present invention are manually operated without the assistance ofpneumatic or electrical power.

The impact tool 100 has a driven member 106 that has means for retainingand driving a fastener about an axis C. In the case where a hexagonalnut 102 is the fastener, the means for retaining and driving thehexagonal nut comprises a mating hexagonal recess 108 which issubstantially shaped and sized to accommodate the hexagonal nut 102therein. Axis C is shown as being centrally located about the drivenmember 106, however, the axis can be offset therefrom without departingfrom the scope or spirit of the present invention.

The impact tool 100 further having a driving member 110 rotatablyconnected to the driven member 106 for driving the driven member 106about the axis C to loosen or tighten the hexagonal nut 102. Preferably,the driven member 106 is cylindrical and housed in a mating cylindricalcavity 112 in the driving member and retained therein so as to rotate.Preferably, the driven member 106 is retained in the cavity 112 by wayof one or more pins 114 which fit into an annular slot 116 on the drivenmember 106. The driven member 106 may also be rotatably retained in thecavity 112 by way of a retaining ring or by other methods known in theart. The driving member 110 generally has a lever or handle connectedthereto which is used to apply a torque and gain a mechanical advantagefor applying a tightening or loosening force to store energy, preferablyin a spring. The lever can be in the form of a “t” handle or a singlecantelevered handle or any other type of handle in which a torque can beapplied to store energy in the spring.

The driven member 106 preferably has a path 118, which is preferablyannular, to couple the driven and driving members 106, 110 by way ofelements for imparting an impact force therebetween. The elements andconfiguration thereof for imparting the impact force between the drivenand driving members 106, 110 vary with the configuration of the impacttool and are not shown in FIG. 1, FIG. 1 being a general representationof the several configurations of the impact tools of the presentinvention.

The elements for imparting the impact force between the driven anddriving members 106, 110 will now be described below with reference toFIGS. 2A-2D. Referring first to FIG. 2A, there is illustrated a firstconfiguration of the impact tool of the present invention in which theimpact tool, generally referred to by reference numeral 100 a, is in aloosening configuration and operates by rotating the driving member 110in a first angular direction B to impart an impact force to the fastener102 and thereafter rotating the driving member 110 in an angulardirection A opposite from the angular direction B before repeating therotation in the direction A. That is, the driving member is repeatedlyrotated back and forth along angular directions A and B until thefastener 102 is adequately loosened.

In the first configuration of the impact tool 100 a of the presentinvention, the driven member 106 further has an impact stop 120 offsetfrom the axis C and in the path 118. An impact mass 122 is also providedin the path 118 and is movable along the path in communication with theimpact stop 120. Also provided are energy storing means for storingpotential energy upon rotation of the driving member 110 relative to thedriven member and energy releasing means for releasing the storedpotential energy such that the impact mass 122 is accelerated to acertain velocity at which time it strikes the impact stop 120.

The energy storing and releasing means preferably comprises a spring 124for biasing the impact mass 122 away from an abutment 126 on the drivingmember 110. The spring 124 is preferably a compression spring disposedin the path 118 between the abutment 126 and the impact mass 122. Thoseskilled in the art will realize that other types of springs, such astension springs and torsion springs can also be utilized to bias theimpact mass 122 away from the abutment 126. The energy storing andreleasing means preferably further comprises a movable stop plate 128biased into the path 118 and movable out from the path 118. The movablestop plate 128 is preferably biased into the path 118 by way ofcompression springs 130 disposed between a bottom portion of the movablestop plate and a bottom of a slot 132 which houses the movable stopplate 128. The movable stop plate 128 is preferably a plate that slidesinside the slot 132 while being biased into the path 118 to block themovement of the impact mass 122. Those skilled in the art willappreciate that the movable stop plate 128 may be rotatable attached tothe driven member by a rotational joint and biased into the path 118 ofmotion of the impact mass 122 by linear, torsional, or flexing springsin bending. The sliding or the rotational joints to move the movablestop plate 128 may be living joints.

The energy storing and releasing means preferably further comprises astop mover 134 which rotates with the driving member 110 for engagingand moving the movable stop plate 128 from the path 118 upon apredetermined angular rotation of the driving member 110. Thus, rotationof the driving member 110 forces the impact mass 122 to abut the movablestop plate 128 and compress the spring 124 until the stop mover 134moves the movable stop plate 128 from the path 118 when the drivingmember 110 is rotated the predetermined angular rotation therebyreleasing the impact mass 122 to accelerate and strike the impact stop120 which transmits an impact force to the fastener 102.

The stop mover 134 preferably has a channel 135 (shown schematically inFIGS. 3A-3F) therein which protrudes into the path 118 and accommodatesthe impact mass 122 therein. The impact mass 122 is biased away from theabutment 126 and is further towards the impact stop 120 then is aleading edge 134 a of the stop mover 134. This permits the impact mass122 to contact the movable stop plate 128 prior to the leading edge 134a of the stop mover 134 to thereby compress the spring 124 and storepotential energy for transfer to the impact mass 122. When the stopmover 134 reaches the movable stop plate 128, it pushes it into the slot132 and out from the path 118 thereby allowing the potential energystored spring 124 to begin to be transferred to the impact mass 122 inthe form of kinetic energy and impact the impact stop 120. To facilitatethe moving of the movable stop plate 128 out from the path 118, themovable stop plate 128 has rounded ends 128 a as shown in FIGS. 4A and4B.

Referring back to FIG. 2A, stop mover 134 can be rigidly attached to thedriving member 110 or have an adjustment means for varying thepredetermined angular rotation and thereby the amount of potentialenergy stored in the spring 124 at the time of releasing the impact mass122 to strike the impact stop 120. Preferably, the adjustment meanscomprises movably mounting the stop mover 134 to the driving means 110such that its position relative to the movable stop plate 128 ischangeable over a predetermined range. That is, the distance between theleading edge 134 a of the stop mover 134 and the movable stop plate 128can be adjusted such that the spring 124 can be compressed more or lessat the time that the stop mover 134 pushes the movable stop plate 128out from the path 118 thereby varying the amount of potential energystored in the impact mass 122. The adjustment means preferably furtherhas a locking means for locking the stop mover 134 in one of a pluralityof positions within the predetermined range.

The adjustment and locking means preferably comprises the stop mover 134having a stud 136 which travels in a slot 138 in a side of the drivingmember 110. The stud further has a lip 140 for retaining a compressionspring 142 on the stud 136. A locking member 144 is disposed on the studand has fingers 146 which mate with corresponding finger holes 148 whichline the slot 138. The fingers 146 of the locking member 144 are biasedfrom the lip 140 and into corresponding finger holes 148 by thecompression spring 142. By way of the adjustment and locking means, thefingers 146 of the locking member 144 can be pulled out of engagementwith the finger holes 148 and the stop mover can be moved to one of aplurality of positions within the predetermined range by sliding thestop mover 134 to its desired location. The stop mover can then belocked in the desired location by releasing the locking member 144thereby engaging the fingers 146 with another set of correspondingfinger holes 148.

A further abutment 150 is preferably provided on the driven member 106such that the driving member 110 can be rotated in direction A until theabutment 126 on the driving member 110 strikes the further abutment 150before repeating the rotation in direction B. Rotation of the drivingmember 110 in direction A until such is prevented by the coincidence ofthe abutments 126 and 150 and provides assurance that a repetitiverotation in direction B can be resumed. Furthermore, the furtherabutment 150 can be used to provide a tightening of the fastener 102when the driving member is rotated in direction A, however, thetightening will not be assisted by an impact force.

Referring now to FIG. 2B, in which like reference numerals denote likefeatures, there is illustrated a second configuration of the impact toolof the present invention in which the impact tool, generally referred toby reference numeral 100 b, is in a tightening configuration andoperates by rotating the driving member 110 in a first angular directionA to impart an impact force to the fastener 102 and thereafter rotatingthe driving member 110 in an angular direction B opposite from theangular direction A before repeating the rotation in the direction B.That is, the driving member 110 is repeatedly rotated back and forthalong angular directions B and A until the fastener 102 is adequatelytightened. Those skilled in the art will recognize that impact tools 100a and 100 b, contain the same elements and their configurations aremerely mirrored from each other.

Referring now to FIG. 2C, in which like reference numerals denote likefeatures, there is illustrated a third configuration of the impact toolof the present invention, in which the impact tool, generally referredto by reference numeral 100 c, is in a loosening configuration andoperates by rotating the driving member in a first angular direction Band continuing rotation of the driving member in the first angulardirection B. That is, instead of the repetitive back and forth motion ofthe impact tools of FIGS. 2A and 2B, impact tool 100 c of FIG. 2Coperates with a continued motion in an angular direction.

In addition to the elements previously described with regard to impacttools 100 a and 100 b, the impact stops 120 of impact tool 100 c havechannels 152, seen more clearly in FIG. 5, which permits the abutment126 and impact mass 122 to pass through. The impact stops 120, as wellas the abutment 126 and impact mass 122 are sized such that they passwithin the channel 135 of the stop mover 134. Furthermore, since impacttool 100 c operates by continued rotation in a single angular direction,the further abutment 150 is eliminated. Lastly, in impact tool 100 c, asecond movable stop plate 154, substantially similar to the movable stopplate 128 (hereinafter referred to as the first movable stop plate 128)shown in FIGS. 4A and 4B, is provided adjacent to the impact stop 120.The purpose of the second movable stop plate 154 will become apparent inthe description of the operation of impact tool 100 c.

Although, the impact tool 100 c can operate with one set of first andsecond movable stop plates 128 and 154 and impact stop 120, it ispreferable to have more than one such set, and more preferable to havetwo impact stops 120, each having the channel 152, and each havingcorresponding first and second movable stop plates 128 and 154 both ofwhich are biased into the path 118 and movable out from the path 118.

The operation of impact tool 100 c will now be described with referenceto FIGS. 3A to 3F in which the annular path 118 is shown as a linearpath for the sake of simplicity. Referring first to FIG. 3A, thepositions of the elements contained in the path 118 is substantiallythat as is shown in FIG. 2C. Upon rotation of the driving member 110 inangular direction B (which is approximated in FIGS. 3A-3F as lineardirection B) the abutment 126 connected thereto drives the impact mass122 through the energy storage spring 124 to contact the first movablestop plate 128 and compress the energy storage spring 124 as shown inFIG. 3B. As discussed previously with regard to impact tool 100 a, theamount the spring 124 compresses can be varied by varying the locationof the stop mover 134 relative to the driving member 110 with theadjustment and locking means. Upon further rotation in Direction B, thestop mover 134 which is fixedly connected to the driving member 110,engages the rounded ends 128 a of the first movable stop plate 128 andpushes it out from the path 118 and into slot 132 which releases thepotential energy stored in the spring 124, and accelerates the impactmass 122 to a certain velocity where the impact mass 122 strikes thesecond movable stop plate 154 as shown in FIG. 3C. Since the secondmovable stop plate 154 is adjacent and preferably touching the impactstop 120, the impact from the impact mass 122 is transferred to theimpact stop 120, the driven member 106 connected thereto, and thefastener 102 retained therein.

Upon further rotation in direction B, the stop mover 134 contacts thesecond movable stop plate 154 engages the rounded ends 128 a thereof andpushes it out from the path 118 and into slot 132 as shown in FIGS. 3Dand 3E. Continuing the rotation of the driving member in direction B,the abutment 126 connected thereto drives the impact mass 122 throughthe channel 152 of the impact stop 120 as shown in FIG. 3E andeventually also drives the abutment 126 through the channel 152 of theimpact stop 122 as shown in FIG. 3F. Continued rotation of the drivingmember 110 drives the stop mover 134 out of engagement with the firstand second movable stop plates 128 and 154 where the springs 130 biasthe first and second movable stop plates 128 and 154 back into the path118 to reset them for the next time the abutment 126, impact mass 122,and stop mover 134 are driven around the path 118.

Referring now to FIG. 2D, in which like reference numerals denote likefeatures, there is illustrated a fourth configuration of the impact toolof the present invention in which the impact tool, generally referred toby reference numeral 100 d, is in a tightening configuration andoperates by rotating the driving member in a first angular direction Aand continuing rotation of the driving member in the first angulardirection A. Those skilled in the art will recognize that impact tools100 c and 100 d contain the same elements and their configurations aremerely mirrored from each other. Thus, the operation of impact tool 100d is substantially similar to that previously described with regard toimpact tool 100 c with the exception of rotation in direction A which isopposite to that of direction B.

Referring now to FIG. 6, there is illustrated another embodiment of theimpact tool of the present invention, generally referred to by referencenumeral 200. The impact tool 200 of FIG. 6 includes both a looseningconfiguration impact tool 100 a, 100 c and a tightening impact tool 100b, 100 d, either of which can be utilized to tighten or loosen afastener 102. Preferably the impact tool 200 has a switching means forswitching between the loosening and tightening portions. The switchingmeans preferably comprises housing the loosening and tightening impacttools 100 a, 100 c; 100 b, 100 d at opposite ends of a common body 202and providing rotation of the common body 202 in one of two positionssuch that in one position the loosening portion 100 a, 100 c is able tocommunicate with the fastener 102 and in the other position thetightening portion 100 b, 100 d is able to communicate with the fastener102. The means for providing rotation preferably comprises a pin 204disposed at a central location of the common body 202 which permitsrotation of the common body 202 relative to a handle 206.

Impact tool 200 preferably further comprises a locking means for lockingthe common body 202 in one of the two positions. The locking meanspreferably comprises a slide 208 movable between locked and unlockedpositions. The slide preferably has an end 210 which engages a portionof the common housing 202 when in the locked position to preventrotation of the common housing 202.

Referring now to FIG. 7, there is illustrated an impact tool, referredto generally by reference numeral 300, which is similar to impact tool200 in that it includes both a loosening configured impact tool 100 a,100 c and a tightening configured impact tool 100 b, 100 d. However,instead of a switching means for switching between the tightening 100 b,100 d and loosening 100 a, 100 c impact tools provided thereon, thetightening 100 b, 100 d and loosening 100 a, 100 c impact tools aremerely provided at different locations on the tool 300, such as onopposite ends 300 a, 300 b as is illustrated in FIG. 7.

In yet another impact wrench of the present invention that can bothtighten and loosen a fastener using impact forces. In this impactwrench, a common driven member is driven by a loosening driving memberand a tightening driving member stacked upon each other and disposedaround the common driven member. A means is then provided to engage thecommon driven member to one of the tightening or loosening drivingmember while disengaging the other. Such a means can be a slide memberthat is slidable between two positions. In one position, an extensionmember on the slide member engages one of the driving members anddisengages from the other. Those skilled in the art will appreciate thatother such means can be used without departing from the scope or spiritof the present invention.

In yet another implementation of the impact wrench of the presentinvention, which is similar in construction to the impact wrenchespreviously described, except the driven member includes a through holehexagonal recess which can retain and drive the fastener. Thus, thefastener can be retained in the through hole hexagonal recess fromeither a first side or a second side of the driven member. Those skilledin the art will appreciate that impact wrench can then be used to eithertighten or loosen the fastener depending upon the side in which thefastener is retained in the through hole hexagonal recess. If theconfiguration of impact wrench were used in this impact wrench,retaining the fastener in the through hole hexagonal recess from firstside would allow the loosening of the fastener while turning the impactwrench over and retaining the fastener in the through hole hexagonalrecess from a second side would allow tightening of the fastener.

The operation of the impact tools have been described in which thedriving member both rotate about a single axis. Such designs arepreferable but not necessary. Those skilled in the art will appreciatethat the axis of rotation of the driving and/or driven members may bedifferent and/or not fixed. One or both motions may even be purelytranslational. Such designs are obtained for example by using a cammechanism or a linkage mechanism or the like to vary the center ofrotation(s). One of the advantages of such designs is that as thedriving member is forced by the operator to rotate and/or translate andas more potential energy is stored in the spring(s) (i.e., as theresistance of the spring to the applied force (torque or moment) isincreased) the operator's leverage is also increased.

Referring now to FIGS. 8 and 9, there is illustrated a first embodimentof the manually operated rotatable impact wrench (hereinafter “impactwrench”), generally referred to by reference numeral 800. The impactwrench 800 includes a driven member 802, which in the preferredimplementation is a solid piece of metallic material, such as forgedtool steel. The driven member has a means for holding a fastener rigidlyattached thereto, such as a lug wrench 807. The driven member 802 andlug wrench 807 can be integrally formed or separately formed andfastened together, such as by welding. The driven member has at leastone anvil surface 808.

A driving member 805 is rotatably disposed on the driven member 802,preferably, at point A by a pin, shoulder screw, or the like. Thedriving member 805 includes at least one impact mass 803 whichcorresponds to the anvil surface 808 when the driven member 802 anddriving member 805 are in their closed position (not shown). In thefirst embodiment of the impact wrench 800, the impact mass 803 isfastened to the driving member 805 by a spring plate 804. The springplate 804 generally is allowed to flex so as to increase the efficiencyof the impact of the impact mass 803 against the anvil surface 808. Thedriving member 805 and impact mass 803 are preferably metallic, such asforged tool steel. The driven member 802 and driving member 805 arebiased together into the closed position, preferably by at least oneextension spring 811, and more preferably two extension springs 811, oneon each side of the driving member 805 and driven member 802.

A lifter cam 806 is rotatably disposed on the driven member 802 and hasat least one finger 806 a for engaging a corresponding cam surface 805 aon the driving member 805. In the first embodiment illustrated in FIG.1, the lifter cam 806 has five such fingers 806 a. The lifter cam 806 ispreferably directly connected to a handle 801 such that rotation of thehandle 801 results in a corresponding rotation of the lifter cam 806.Alternatively, the lifter cam 806 and handle can be connected through alinkage or gearing system to provide the desired rotation of the liftercam 806.

The operation of the impact wrench 800 will now be described withreference to FIGS. 8 and 9 and although the same is described in termsof loosening a lug nut fastener (not shown), it can also be configuredto tighten a lug nut fastener or loosen and/or tighten any other typesof fasteners. Alternatively, a similar configuration can be used toprovide an impact facilitate cutting a wire or branch or other similarwire-type members. When the handle 801 is rotated in a counter-clockwisedirection one of the fingers 806 a of the lifter cam 806 engages the camsurface 805 a near the pivot point A. As the lifter cam 806 continues torotate in the counter-clockwise direction, the driving member 805 isforced to rotate about point A against the biasing force of the springs811 until the finger 806 a reaches the end of the cam surface 805 a, asis shown in FIG. 8. Continued rotation of the handle 801 and the liftercam 806 rotated therewith causes the driving member 805 to acceleratetowards the driven member 802 due the energy stored in the extensionsprings 811. The driving member 805 continues its acceleration until theimpact mass 803 impacts the anvil surface 808. The impact force from theimpact is transferred through the driven member 802 and to the lugwrench 807 rigidly connected thereto. This operation is repeated untilthe lug nut or other fastener is loosened. Since the lifter cam 806 inthe impact wrench of the first embodiment has five fingers 806 a, therewill be five impacts per revolution of the handle 801.

Referring now to FIGS. 10 and 11 there is illustrated a secondembodiment of the impact wrench of the present invention, generallyreferred to by reference numeral 900. In FIGS. 10 and 11, like referencefeatures are represented by reference numbers in a 900 series ofnumbers. Thus, handle 901 is similar to handle 801. Impact wrench 900 issimilar to impact wrench 800 except that the impact mass 903 is rigidlyconnected to the driving member 905, and is preferably integrally formedtherewith. Furthermore, lifter cam 906 has three fingers 906 a and isfreely rotatable independent of the handle 901. That is, the handle 901and lifter cam 906 rotate independently and are thus not rigidlyconnected to each other. However, rotation of the handle 901 causes thelifter cam 906 to rotate. Handle 901 includes a pin 906 offset from theaxis of rotation of the handle 901 which engages an inner surface 906 bof each finger 906 a and forces the lifter cam 906 to rotate. The handleis shown in FIGS. 8 and 10 broken away to reveal details of underlyingelements, it is shown whole by dotted line. The remaining operation ofimpact wrench 900 is similar to that previously described with regard toimpact wrench 800. However, since the cam lifter 906 of impact wrench900 has three fingers 906 a, each revolution of the handle 901 willproduce three impacts. The number of fingers 806 a, 906 a on the liftercams 806, 906 are shown by way of example only and not to limit thescope or spirit of the present invention, any number of such fingers 806a, 906 a can be utilized, such as two fingers 1006 a shown in the liftercam 1006 of FIG. 12.

Although a single impact mass 803, 903 and anvil surface 808, 908combination is illustrated in FIGS. 8 and 10, it will be appreciated bythose skilled in the art than one such combination may be utilizedwithout departing from the scope or spirit of the present invention.FIG. 13 illustrates one such configuration of an impact wrench havingtwo impact mass/anvil surface pairs, the impact wrench of FIG. 13 beinggenerally referred to by reference numeral 1000. Impact wrench 1000 usesthe arrangement of impact wrench 900 mirrored over the x and y axes toprovide a configuration in which two impacts are produced nearlysimultaneously. The simultaneous impacts can theoretically double theamount of impact produced or alternatively, the wrench can be scaled inhalf and produce the same impact as the impact wrench in FIG. 10.

Referring now to FIG. 13, where like numerals refer to similar features(e.g., handle 1001 is similar to handle 901 and 801) an impact wrenchhaving multiple impact masses is illustrated therein, referred togenerally by reference numeral 1000. Those skilled in the art willrealize that impact wrench 1000 operates similarly to impact wrench 900except that the handle 1001 has two pins 1001 a, each of which engagesan inner surface 1006 b of a corresponding lifter cam 1006 to rotate thelifter cam 1006 b such that fingers 1006 a engage a corresponding camsurface 1005 a. Such a motion rotates the driving member 1005 aboutpoint A to store energy in springs 1011. After the fingers 1006 a passthe cam surface 1005 a, the springs 1011 bias the impact masses 1003 toimpact the anvil surfaces 1008 of the driven member 1002. Although, twocam lifters 1006 are shown, only one is necessary.

Referring now to FIGS. 14A-14D there is illustrated a third embodimentof the impact wrench of the present invention. The impact wrench beinggenerally referred to by reference numeral 1100. Referring first toFIGS. 14A and 14B, the impact wrench 1100 includes a shell 1102 which isrigidly connected to a fastener (not shown) preferably with a lug orsocket wrench (not shown). The fastener is preferably in line withcenter A and not offset therefrom. The shell 1102 has at least one andpreferably a plurality of anvils 1104 rotatably disposed therein suchthat they rotate about points B in the directions of arrows C withinwindows 1103 cut in the wall of the shell 1102. Point B preferablyincludes a pinned joint. The anvils are biased inwards towards thecenter A preferably by a torsion spring (not shown) at point B. A handle(not shown) is rigidly attached to follower plates 1106, which rotateinside the shell 1102 as the handle is rotated. The follower plates 1106have long arms 1106 a which engage the anvils and pushes them outwardsfrom the interior of the shell as shown in FIG. 14D. The follower platesalso have short legs 1106 b which clear the anvils 1104 and do notinterfere with such when rotated inside the shell 1102 as is also shownin FIG. 14D. The follower plates 1106 preferably are the same width asthe anvils 1104.

The impact wrench also includes impact masses 1108 offset from center Aby a flexible material 1110 such as a leaf spring, extension spring, ora piece of spring steel with a curved cross section. One end of theflexible material is connected to the impact mass 1108 and the other endis connected to the handle or an extension thereof (such as the followerplate) so as to rotate with the rotation of the handle (and followerplate). As shown in FIG. 14B, the width of the impact mass 1108 is suchthat it fits between the follower plates 1106. Although not necessary,at least one further spring 1112 can be connected between each impactmass 1108 and a corresponding short leg 1106 b of the follower plate1106.

The operation of the impact wrench 1100 will now be described withregard to FIGS. 14A-14D. As the handle is rotated counterclockwise, thefollower plate 1106 and impact masses 1108, being connected thereto alsorotate counterclockwise. However, as shown in FIG. 14C, the rotation ofthe impact masses 1108 are blocked by a corresponding anvil surface1104. Therefore, the flexible material 1110 will bend (and store energy)and the spring 1112 will stretch (also storing energy) until the longleg of the follower plate 1106 a engages the anvil 1104 and push it outfrom the interior of the shell 1102 as shown in FIG. 14D. At which pointthe stored energy in the flexible material 1110 and spring 1112 willcause the impact mass 1108 to accelerate towards the next anvil surface1102 (which has not been engaged by the short leg 1106 b of the followerplate 1106 and thus not pushed from the shell). The impact mass 1108will thus impact the anvil 1104 and transfer the impact to the shell1102 and fastener connected thereto. Although only one impact mass 1108is shown in FIGS. 14C and 14D, it is understood that two such massesimpact a corresponding anvil simultaneously. Furthermore, the impactwrench can be designed with N anvils and N/2 simultaneous impacts.

Referring now to FIG. 15, there is shown a schematic representation of amanually operated impact cutting tool, for cutting wires, tree branchesand the like. The impact cutting tool illustrated in FIG. 15 isgenerally referred to by reference numeral 1200. Cutting tool 1200 hasfirst and second cutting jaws 1202, 1204 pivot about pivot point A.Cutting jaws 1202 and 1204 are configured as those well known in the artfor cutting bolts, branches, wires and the like. The first cutting jaw1202 is connected to a first handle 1206, while the second cutting jaw1204 is connected to an impact handle 1208. Impact handle 1208 has ananvil surface 1209 at its free end. The first handle 1206 and impacthandle 1208 pivot about point A to open and close the first and secondcutting jaws 1202, 1204 relative to each other. Cutting tool 1200further has a second handle 1210 pivotally connected to the first handle1206 at pivot point B, which is offset from pivot point A. The cuttingtool 1200 further has an impact mass member 1212 having an impact mass1214 at one end thereof. The impact mass member 1212 is pivotablydisposed on the impact handle 1208 about pivot point C. The impact mass1214 is biased towards the anvil surface 1209 of the impact handle 1208,preferably by extension springs 1216. A projection 1218 is provided onthe second handle 1210 to engage a free end 1212 a of the impact massmember 1212.

The operation of the impact cutting tool will now be described withregard to FIG. 15. The first and second cutting jaws 1202, 1204 areopened relative to each other by spreading apart the first and secondhandles 1206, 1210 to permit the member (branch, wire, bolt, etc.) to becut to be disposed therebetween. The first and second handles 1206, 1210are then pushed towards each other to sandwich the member to be cutsecurely between the first and second cutting jaws 1202, 1204. After themember to be cut is within the first and second cutting jaws 1202, 1204,any further movement of the first and second handles 1206, 1210 towardseach other will result in the projection 1218 engaging the free end 1212of the impact mass member 1212 to rotate the same such that the impactmass 1214 moves away from the anvil surface 1209 against the biasingforce of the springs 1216, to thus store energy in the springs 1216.Upon continued movement of the second handle 1210 towards the firsthandle 1206, the projection 1218 disengages with the free end 1212 a ofthe impact mass member 1212 thus releasing the energy stored in thesprings 1216 causing the impact mass 1214 to accelerate towards theanvil surface 1209 and impact the anvil surface 1209. The impact istransferred through the impact handle 1208 and to the second cutting jaw1204 that impacts the member to be cut. A ratcheting mechanism ispreferably provided on the projection 1218 or free end 1212 a to allowthe second handle 1210 to be reset to begin another impact. A ratchetmechanism can also be provided at pivot point C such that the secondhandle 1210 can be “pumped” to build up a lot of energy in the springs1216 before it is released to cause the impact. Although the longer thelength L of the impact handle 1208, the greater the moment arm, andgreater the impact transferred to the second cutting jaw 1204, if L istoo long it will be flexible and will not efficiently transfer theimpact. Therefore, there is a tradeoff between having a stiff impacthandle 1208 and a long impact handle 1208. Those skilled in the art willrealize that FIG. 15 represents a schematic illustration of an impactcutting tool, and that numerous configurations are possible to achievethe desired cutting impact.

Referring now to FIG. 16, there is shown a schematic representation of amanually operated impact punch tool for cutting holes, notches etc. insheet metal and other sheet materials. Impact punch is generallyreferred to by reference numeral 1300. Punch 1300 has a first handle1302 with a sleeve 1304 at an end thereof for slidably retaining a punch1306 therein. The punch 1306 has an anvil surface 1308 at one end and apunch edge 1310 at the other end. A clamp member 1312 is rotatablydisposed on the first handle 1302 to pivot about point A. The firsthandle 1302 and clamp member 1312 have opposing surfaces 1314 to clamp awork piece 1316, such as sheet metal therebetween. The opposing surfacespreferably have an elastomer insert 1318 for gripping the work piece1316. A screw 1320 is captured in the first handle by a ball tip 1322and mates with a corresponding thread in the clamping member 1312. Aknob 1324 is provided on the screw 1320, turning which acts to clamp orrelease the work piece 1316 between the opposing surfaces 1314.

An impact mass 1326 is provided on rails 1328 to slide freely along thedirections of arrow B. The rails 1328 are fixed in the sleeve 1304 atone end and have a lip 1330 at another end for retaining compressionsprings 1332 between the lip 1330 and impact mass 1326. Although tworails are shown, four are preferred. The impact mass 1326 has a pin 1334projecting from at least one side of the impact mass 1326. A secondhandle 1336 is also provided which pivots about point A. The secondhandle has a spur 1338 at one end thereof for engaging the pin 1334. Thespur 1338 preferably has a ratchet mechanism which permits clockwiserotation of the spur 1338 and which locks the spur 1338 from rotating ina counterclockwise rotation.

The operation of the impact punch 1300 will now be described with regardto FIG. 16. The work piece 1316 is placed between the opposing surfaces1314 and the punch 1306 is aligned with a center of a hole to be punchedon the work piece 1316. After alignment, the knob 1324 is turned toclamp the work piece 1316 securely between the opposing surfaces 1314.The first and second handles 1302, 1336 are pressed towards each other,which lifts the impact mass 1326 against the bias of the springs 1332.When the spur 1338 disengages from the pin 1334 the impact mass 1326accelerates towards the anvil surface 1308 and impacts the same. Theimpact is transferred to the cutting edge 1310 of the punch 1306, whichpunches a hole in the work piece. The cutting of the hole may occur in asingle impact or after repeated impacts. After the impact, the secondhandle 1336 is lifted away from the first handle 1302 (either manuallyor by a biasing spring, not shown) such that the spur 1338 engages thepin 1334 and rotates clockwise back into an engagement position in whichanother impact can be initiated. A similar ratcheting spur and pin maybe used at the projection 1218 and free end 1212 a of the cutting tool1200 described above.

While there has been shown and described what is considered to bepreferred embodiments of the invention, it will, of course, beunderstood that various modifications and changes in form or detailcould readily be made without departing from the spirit of theinvention. It is therefore intended that the invention be not limited tothe exact forms described and illustrated, but should be constructed tocover all modifications that may fall within the scope of the appendedclaims.

1. A manually operated rotatable impact tool comprising: a driven memberhaving means for retaining and driving a fastener about an axis, thedriven member further having at least one impact stop offset from theaxis; a driving member rotatably connected to the driven member fordriving the driven member about the axis to loosen or tighten thefastener; an impact mass movable along a path in communication with theimpact stop; a spring disposed in the path for storing energy uponrotation of the driving member; and energy releasing means for releasingthe stored energy and allowing it to be at least partially transferredto the impact mass such that the impact mass accelerates and strikes theimpact stop upon the release of the stored energy.
 2. The impact tool ofclaim 1, wherein the fastener is a hexagonal nut and the means forretaining and driving the hexagonal nut comprises a mating hexagonalrecess for containing the hexagonal nut therein.
 3. The impact tool ofclaim 2, wherein the driven member is cylindrical and the driving memberhas a mating cylindrical recess for containing the driven membertherein.
 4. The impact tool of claim 3, wherein the driving memberfurther has a lever for applying a torque to the driven member andhexagonal nut contained therein.
 5. The impact tool of claim 1, farthercomprising an abutment on the driving member, wherein the spring is acompression spring disposed in the path between the abutment and theimpact mass.
 6. The impact tool of claim 1, farther comprisingadjustment means for varying a predetermined angular rotation of theimpact mass and thereby the amount of energy stored in the impact massat the time of releasing the impact mass to strike the impact stop. 7.The impact tool of claim 1, wherein rotation of the driving member in afirst angular direction loosens the fastener.
 8. The impact tool ofclaim 1, wherein rotation of the driving member in a first angulardirection tightens the fastener.
 9. The impact tool of claim 1, whereinrotation of the driving member in a first angular direction loosens thefastener and rotation of the driving member in a second angulardirection opposite the first angular direction tightens the fastener.10. The impact tool of claim 1, wherein the impact mass strikes theimpact stop upon the rotation of the driving member in a first angulardirection and the impact mass strikes the impact stop subsequently byrotation of the driving member in a direction opposite the first angulardirection followed by rotation of the driving member in the firstangular direction.
 11. The impact tool of claim 1, wherein the impactmass strikes the impact stop upon the rotation of the driving member ina first angular direction and the impact mass strikes the impact stopsubsequently by continued rotation of the driving member in the firstangular direction. 12-20. (canceled)